GPS performance can be affected by which factors?

• A. Satellite geometry, weather, and interference
• B. Battery life
• C. Time of day only
• D. Operator experience

Answer: (A)

GPS performance hinges on how well the satellite signals can be received and solved for a position. Satellite geometry matters because a wide, well-distributed spread of satellites across the sky gives the receiver multiple independent line-of-sight measurements, reducing dilution of precision and yielding faster, more accurate fixes. When the visible satellites cluster in one part of the sky, geometry is poor, and accuracy suffers.

Atmospheric conditions also play a role. The signal travels through the ionosphere and troposphere, where delays and refraction can introduce errors in the measured travel time. These delays vary with atmospheric state, including moisture, temperature, and solar activity, so they can degrade accuracy and integrity, even though receivers model and mitigate much of it.

Interference encompasses any external RF disruption, such as jamming, spoofing, or other electronic noise, which can overwhelm or corrupt the GPS signals, causing loss of lock or erroneous position readings.

The choices about battery life, time of day, or operator experience don’t change the fundamental signal propagation and geometry effects, so they don’t inherently define GPS performance in the same way.